1. Field of the Invention
The present invention relates generally to catheters and more particularly to a device which provides controlled delivery of a guide tip of a catheter within a lumen having chronic total occlusion.
2. Description of the Related Art
Cardiovascular disease is a leading cause of mortality worldwide. Often times, cardiovascular disease occurs upon chronic total occlusion (CTO) of an artery of a patient. CTO typically occurs after a patient develops atherosclerosis. Blockage of an artery may occur in coronary, peripheral or other arteries. As the blockage continues over time, the blockage become chronic, thereby leading to CTO.
In order to minimize the potential effects of CTO, passage of blood must be restored to the artery. In the past, attempts to restore blood flow included passing a guidewire through the occlusion, thereby forming a passage through which blood may flow. Nonetheless, while attempting to penetrate the occlusion, the guidewire may inadvertently penetrate a subintimal space between the intimal layer and the adventitial layer of the blood vessel. Once this occurs, redirection of the guidewire back into the blood vessel lumen is nearly impossible. Therefore, the user must pull the guidewire from the subintimal space and start the procedure over thereby increasing the time and overall costs associated with returning blood passage to the artery having CTO.
Moreover, during insertion of the guidewire into the lumen, the configuration of prior art catheter devices allowed for accidental deployment of the guidewire during manipulation of the catheter device. As described in U.S. Pat. No. 6,217,527, the disclosure of which is hereby incorporated by reference, the motion required to deploy a guidewire from a prior art catheter device was the same as the motion for inserting the catheter device into a lumen. To further illustrate, a user introduces a prior art catheter device into the vasculature of a patient using a lateral motion relative to the catheter device. Upon insertion of the catheter device into the arterial lumen, the user deploys the guidewire within the lumen using the same lateral motion relative to the catheter device. As such, during the operation of inserting the catheter device into the lumen, the user may accidentally deploy the guide, thereby potentially damaging the lumen.
In addition to passing a guidewire through the occlusion, past attempts have included forming a subintimal lumen through the subintimal space of the lumen. A user employing this method passes a guidewire between the intima and the adventitia of the lumen. Once the guidewire passes through the subintimal space, the user dissects the subintimal space with an angioplasty balloon and then performs a stenting operation. Upon stenting, an acceptable lumen is formed which bypasses the CTO altogether.
As disclosed in U.S. Pat. No. 6,217,527, a user inserts a guidewire into the subintimal space on one side of the occlusion. Upon insertion of the guidewire, the user inserts a catheter over the guidewire into the subintimal space. The catheter includes a tip configured for penetrating a portion of the arterial wall at a distal side of the occlusion. However, the user must accurately deploy the guide tip within the lumen in order to avoid damaging an arterial wall of the lumen. For example, the user may over deploy the catheter such that the guide tip penetrates the subintimal space, passes through the intended lumen and contacts the arterial wall on the opposite side of the intended lumen, thereby potentially injuring the patient. In addition, prior art guide tips were constructed of flexible material which decreased penetration capabilities of the guide tip through the subintimal space.
Accordingly, a need exists for an automated device which allows precise advancement of a guide tip deployed within a subintimal space of a patient. This new device should include a guide tip resistant to imparted bending forces during penetration of a subintimal space of an arterial wall. The new device should also minimize the possibility of inadvertent deployment of a guide tip during use of the device.
The present invention fills the aforementioned needs by providing a catheter device which incrementally advances a guide tip through a subintimal space of a patient. The present invention also provides a method for incrementally advancing a guide tip through a subintimal space of a patient.
In an embodiment of the present invention, a device for advancing a guide tip through a lumen is disclosed. The device includes a housing having a radial groove, a bushing and an inner key. The bushing is disposed within the housing and operatively couples with the housing via a bushing thread such that the bushing incrementally advances within the housing. The inner key couples with both the bushing at a proximal end of the inner key and a guide tip via a braided shaft at a distal end of the inner key. The guide tip couples with the inner key such that as the bushing incrementally advances within the housing, the guide tip incrementally advances within the lumen. In addition, a flex guide having a slot configuration couples with the guide tip such that the flex guide also deploys into the lumen during use of the catheter device.